Comparative study of two methods for rare earth elements analysis in human urine samples using inductively coupled plasma-mass spectrometry

Abstract

The application of rare earth elements (REEs) in several areas, including high-tech technology, agriculture, medicine, and fuels, has made them an essential component of our everyday life. This extensive use of REEs in several technologies is expected to potentially impact human health. Even if several studies investigated the levels of REEs in human matrices, until now no standard method has been established for analyzing these elements in human matrices. The sample analysis should be of high quality, and the methods should be validated properly to ensure the quality of the procedure and traceability of the analytical data. In this research, we compared the validation and effectiveness of two different methods of sample preparation for human urine samples: a simple dilution of the sample (DIL) was compared with microwave assisted-acid decomposition (MIN) for tracing REE levels in human urine samples. The analysis was carried out by inductively coupled plasma mass spectrometry (ICP-MS). The working conditions have been set in high-sensitivity mode. Accuracy of the proposed method was evaluated by spiking the sample matrix with known concentrations of analyte standards. Both methods showed adequate precision of repeatability and intra-laboratory reproducibility, with the DIL method showing better precision of both repeatability and reproducibility than the MIN method. The CVr% values of repeatability range from 1.5 to 12% for the DIL and from 8.4 to 16% for the MIN method. The CVr% values of reproducibility range from 6.2–23% for the DIL and from 8.6 to 24% for the MIN method. REE recoveries for both methods were very close to 100%. Both methods proved to be effective for the determination of REE levels in human urine matrices.

Atomic spectrometry update: review of advances in the analysis of clinical and biological materials, foods and beverages

“…They concluded that, despite taking longer and being less cost-effective, the MAD method was preferred. A similar comparison was made by Brouziotis et al 45 for the determination of REEs in human urine by ICP-MS: urine was either diluted (1 + 4) with 2% (v/v) HNO 3 or subjected to MAD in a sealed vessel (2 mL urine, 0.5 mL conc. HNO 3 , final volume 10 mL).…”

Validation of microwave acid digestion, diffusive gradients in thin-film preconcentration and inductively coupled plasma optical emission spectrometry methodology for the determination of REEs in natural zeolites

“…For example, Brouziotis et al , 26 developed a methodology for REE analysis in human urine samples and calculated instrumental LODs for ICP-MS in the range of 0.001–0.004 μg L −1 . Kukusamude and Kongsri 47 developed and validated a method for REE determination in rice using ICP-MS and reported LODs between 0.07 and 0.010 μg L −1 .…”

“…ICP-MS is known for its susceptibility to isobaric interferences that can affect the accuracy of REE measurements, i.e., the presence of barium oxides can interfere with LREEs such as Nd, Sm and Eu, while oxides of LREEs (e.g., CeO and NdO) interfere with some HREEs (e.g., Gd, Tb, and Dy). 26 Modern ICP-MS instruments are equipped with collision or reaction cells that can eliminate these interferents. For laboratories equipped only with ICP-OES, the development of analytical methods based on this technique and capable of providing accurate results for the analysis of REEs in complex matrices is of great interest.…”

“…, Gd, Tb, and Dy). 26 Modern ICP-MS instruments are equipped with collision or reaction cells that can eliminate these interferents. For laboratories equipped only with ICP-OES, the development of analytical methods based on this technique and capable of providing accurate results for the analysis of REEs in complex matrices is of great interest.…”